dc2019q - VeryAndroidoso
This was a jeopardy challenge, part of dc2019q. (CTFtime)
Was solved by: 33 teams
This challenge is solved offline, there's no server side component.
With the right flag, it will print 'Success!' on the screen and on logcat. Good Luck!
Reverse engineering and Frida is a valid way to solve this challenge, and many teams opted to do this.
However, this challenge is also solvable using angr's symbolic execution -- see the author's writeup for hints on this route.
None yet :(
If you wish, you can contribute some.
There's an author-recommended writeup.